Back pressure valve



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Feb. 27, 1940. K. H. SWART BACK PRESSURE VALVE Filed Sept. 14, 1959Patented Feb. 27, 1940 UNITED STATES PATENT OFFICE 'BACK PRES SURE VALVEKenneth H. Swart, Whittier, Calif., assignor to Security Engineering00., 1110., Whittier, Calif., a corporation of California ApplicationSeptember 14, 1939, Serial No. 294,818

Claims. (CI. 166-1) This invention relates to improvements in back Fig.2 is a horizontal section taken substanpressure valves used forcementing cas 1 the line upon 1; liners, and the like in n u h as oilwells. Flg. 3 a vertical section through a valve- Heretofore backpressure valves have been supporting bushing embodying a slightlydifler- 5 devised for maintaining the pressure at which out form ofdesign; a

the cement was forced out of the casing or liner Fig. 4 is a partialview in vertical section ilas the case may be and preventing reverseflow lustrating one of the back pressure check valves. into the casingor liner wherein the valves are Referring to th ace mounted on theexterior of the ported collar or in similar reference charactersdesignate simi- 10 other structure through which the cement is disp rtsthroughout, the improved back pr charged. In some instances these valveshave Su e valve compris been recessed in the exterior of the portedcollar may be in the form 01' or other structure. It is found, however,that of flush joint with the valves externally mounted there is danmaybe either a collar or a se 16 ger of injuring them upon lowering thecasing which, in turn, either may or may not be formed or liner into thewell so that they will not seat of readily drillable material. In theconstrucproperly to prevent reverse flow when the distron shown in Fig.1 1 charge of cement is discontinued. Even when of a coll threaded atthe valve is recessed it not infrequently occurs l2 to enable its being20 that mud or other detritus enters the recesses or of casing r linenThe otherwise damages the valves and prevents their plurality of radialports functioning properly. tom it is P vided with a An object of thepresent invention is to prold above which it is internally th as at 5vide an improved back pressure valve wherein Within the sleeve there isdisposed a valve-sup:

the check valves which prevent reverse flow P ng bushing generallyindicated at l6, which 26 through the ported collar or other structureare 15 preferably formed of readily drillabl material, adequatelyprotected against injury on lowering Such as for mple aluminum or analloy of the device into a well for the purpose of cement-' aluminumsuch as that now known in t trade ing. The invention contemplates ameans for l the d -name Securaloy. This bushing 30 providing an externalsleeve within which there S in the nature of a tubular body having. it30 is a valve-holding or valve-suppor in hi lower end xternally threadedto enable its being on which the valves are mounted, these valvesScrewed into sleeve Ill and tightened th being fully protected by thesurrounding sleeve. against shoulder I4. It is equipped with a plu- Thebushing is preferably formed of readily drilly of ports I! which, whenthe parts are as- 85 ablgmaterial so that it may be drilled up uponsemblecl, are preferably, but not necessarily, (115- 85 completion ofthe cementing. aligned with respect to ports l3 as sh in Morespecifically, another object of the inven- Fig. 2. tion is to provide ameans for holding thebush- On the exterior of the bushing there i for ding' against rotation within the sleeve within an annular groove orchannel l8 arranged oppo- 40 which it is mounted so that on drilling upthe site ports I3 and placing these ports in communi- 40 bushing thereis no danger of its merely being cation with port l'l. Above thischannel the excaused to turn within the sleeve which would ol 0f thebushing is externally reduced t hinder the drilling. P vide for theattachment of downwardly ex- With the foregoing and other objects inview, tending Sprmgs which are disposed e y which will be made manifestin the following Withm the channel Each spring l9 carries a detaileddescription and specifically pointed out g which together with itsssociated rub in the appended claims, reference is had to the er was erconstitutes an outwardly-Open- 111g, ly-closing check valve adapted toseat accompanying drawmtg for an rllustratlve emin ports n to permitoutward flow e ethmugh bodiment of my inven ion, wherein:

Figure 1 is a vertical section through the outer but preventing reverseThese buttons may be attached to the ends of th sleeve or collarillustrating the bushing therein, 6 sprmgs by means of screws 2| whichextend through holes in the part of the bushing being shown in elevationand springs rather loosely so that the buttons or the remainder beingbroken away and shown valves have a small floating action with respectin vertical section; to their springs and on seating may accommodatethemselves to the seats at the outer ends of the ports l1. Between eachrubber washer and its respective spring there is preferably a metalwasher 20b. The rubber washer has a comparatively flexible peripherallip designed to seat on a flat seat formed on the exterior of thebushing. The arrangement is such that the rubber washer is normallycaused to engage its seat slightly in advance of the seating of themetal button 20 as the valves move from open to closed position. Thisform of construction is preferable in that leakage is prevented and thevalves are caused to close even when there exists only slight backpressures.

In the top of the bushing there is formed a groove designed to receivepacking 22, such as for example chevron packing, which will effectivelyseal the top of the bushing and the top of the sleeve against leakagetherebetween.

In the form of construction shown in Fig. l, the bottom of the bushingis closed as by a baflie 23 permitting the casing to be floated into thewell. In the construction shownin Fig. 3 this baiile is equipped with avalve 24 which is upwardly opening to permit entry of fluid while thestructure is being lowered into the well and which is downwardly closingso that when cement is forced downwardly through the casing it will bestopped by this valve and caused to be discharged through ports I! andI3. In some forms of construction the baiile may be omitted entirely.That is, the interior of the bushing may be opened at its bottom as wellas at the top. Such a construction may be employed where other means ispresent to cause the cement to be forced outwardly through the ports.

The type of check valve shown which is made up of the springs l9 and thebuttons 20 is that type which is generally referred to in this art as asaxophone valve. It will be noted that in the present construction thesesaxophone valves are completely protected by the surrounding sleeve |0so that when the device is lowered into the well there is no danger ofthese valves being damaged. With the ports l3 and I1 disaligned even ifthe ports l3 should be plugged by mud, such as by scraping the walls ofthe well when the structure is being lowered into position the mud orformation which plugs the ports does not have an opportunity to damagethese saxophone valves. Upon forcing fluid downwardly through the casingor cementing string any plugging mud that may be present will be forcedback out through the ports I3. The construction thus is such that noopportunity for material to lodge underneath the'valves to prevent theirseating properly is afi'orded. Consequently, the valves are always freeto seat to prevent reverse flow through the structure when the dischargeof cement is discontinued.

When the discharged cement has set the bushing is intended to be drilledup to leave the casing or liner as the case may be free or open forfurther operations. As the bushing is tightened against the shoulder l4,it is manifest that it cannot rotate within the sleeve while beingdrilled up. Also, it is impossible to bodily force the bushing throughthe sleeve because of the presence of the shoulder. In this way, thereis assurance that the bushing and its associated parts can be completelyreduced to small cuttings which can be flushed out of the well by thecirculation fluid to leave the casing or liner clear for furtheroperations.

Various changes may be made in the details of construction withoutdeparting from the spirit or scope of the invention as defined by theappended claims.

I claim:

1. A back pressure valve for cementing casings, liners, and the likecomprising means providing an outer ported sleeve, a drillable portedvalveholding bushing therein, and outwardly-opening, inwardly-closingcheck valves on the bushing for opening and closing the ports in thebushing, said check valves being arranged between the bushing and thesleeve so as to be protected by the sleeve when the device is loweredinto a well.

2. A back pressure valve for cementing casings, liners, and the likecomprising means providing an outer ported sleeve, a drillable portedvalve-holding bushing therein, and outwardlyopening, inwardly-closingcheck valves on the bushing for opening and closing the ports in thebushing, said valves being in the form of springs secured to the bushingand carrying buttons adapted to seat in the ports in the valve holder,the buttons and springs being arranged between the bushing and sleeve soas to be protected by the sleeve when the device is lowered into thewell.

3. A back pressure valve for cementing casings, liners, and the likecomprising means providing an outer ported sleeve, a drillable portedvalve-holding bushing therein, and outwardlyviding an outer portedsleeve, a readily drillable ported valve-holding bushing in the sleeve,there being an external annular channel in the bushing opposite theports therein and opposite the ports in the sleeve, springs mounted onthe bushing and disposed in the channel, and buttons on the springsadapted to seat in and close the ports in the bushing against inwardflow therethrough.

5. A back pressure valve for cementing casings, liners, and the likecomprising means providing an outer ported sleeve, a readily drillableported valve-holding bushing in the sleeve, there being an externalannular channel in the bushing opposite the ports therein and oppositethe ports in the sleeve, springs mounted on the bushing and disposed inthe channel, and buttons on the springs adapted to seat in and close theports in the bushing against inward flow therethrough, said buttonsbeing loosely mounted upon the springs.

6. A back pressure valve for cementing casings, liners, and the likecomprising means providing an outer ported sleeve, a readily drillableported valve-holding bushing in the sleeve, there being an externalannular channel in the bushing opposite the ports therein and oppositethe ports in the sleeve, springs mounted on the bushing and disposed inthe channel, and buttons on the springs adapted to seat in and close theports in the bushing against inward flow therethrough, packing means onthe bushing above the channel, the bushing below the channel beingthreaded into the sleeve, there being a shoulder in the sleeve againstwhich the bushing may be tightened to prevent rotation of the bushing inthe sleeve while it is being drilled up.

7. A back pressure valve for cementing casings.

a ported sleeve, a drillable ported valve-holding bushing in the sleevehaving ports arranged to supply cement to the ports in the sleeve,inwardly closing check valves for the ports in the bushing, there beinga shoulder on the sleeve against which the bushing may tighten toprevent rotation of the bushing while it is being drilled up.

8. A back pressure valve tor'cementing casings, liners, and the likecomprising means pro-- viding an outer ported sleeve, 2 drillable portedvalve-holding bushing therein, outwardly opening, inwardly-closing checkvalves on the bushing for opening and closing the ports in the bushing,said check valves being arranged between the bushing and the sleeve soas to be protected by the sleeve when the device is lowered into a well,and means for preventing downward flow 10 through the bushing.

9. A back pressure valve for cementing casings, liners. and the likecomprising means providing an outer ported sleeve, 2. drillable portedvalve-holding bushing therein, outwardly-opening, inwardly-closing checkvalves on the bushing for opening and closing the ports in the bushing,said check valves. being arranged between the bushing and the sleeve soas to be protectedby the sleeve when the device is lowered into a well,and means iorpreventing downward flow through the bushing, butpermitting upward flow .therethrough.

10. A back pressure valve for cementing cas ings, liners, and the likecomprising means providing an outer ported sleeve, a ported bushingtherein, and outwardly opening, inwardly closing check valves foropening and closingthe ports in the bushing, said check valves beingarranged

